The Allomantic Alcubierre Drive (FTL)

[Steeldancer he/him]

So today I was at work and was thinking about allomancy and FTL technology when I realized that speed bubbles compress space. I can't believe no one has mentioned this before, so I'll act as if this has been proposed before and try and add as much detail as possible. Since I had many hours to work this out, here's what I have:

I am basing this on the idea that the cosmere still has einsteinian physics, because I don't think Brandon is just throwing out all that stuff. He's relying on that. And here, there was an idea for a FTL drive called the alcubierre drive. The basic idea is that while no THING can move faster than light, space-time can. So, like surfing a wave, you compress space in front of you, and expand space behind you, and end up going faster than light. So, what I realized is that a speed bubble can't be dilating time without dilating space to some degree or another. Obviously it's not a huge amount, because it's not affecting the people inside enough for anyone to go "huh, this is weird." But, if you're compressing time, you should also to some degree be compressing space as well, based on the whole idea of space-time. And that means with 2 bubbles, you could potentially achieve FTL travel.

This idea has several things going for it, but obviously there's a bit more to this process than just a slider and a pulser in a rocket ship. First, this is a relatively viable method of FTL travel, given that unlike many other methods in stories, it doesn't break hard physics. The main issue in the real world is that we don't have a great way to compress space and expand space in the way that an alcubierre drive would require. But huh, look at that! Coincidentally, Bendalloy and Cadmium EXACTLY fit the bill for what you would need! It's almost as if Brandon read about the alcubierre drive at some point, and decided to create speed bubbles to fit the bill, so that they could be around as a power but then later on be realized for their greater potential! Even recently, he's mentioned that there's more to speed bubbles in relation to FTL travel that we haven't figured out yet, and we've gone on and on about the ability for cadmium to enable a "cryosleep" of sorts. This would exactly fit the bill for something reasonable for them to discover in the future once they have a better understanding of realmatics and physics. 

Speaking of which, real quick, I'll list off what Scadrial needs to get to to have this be a viable technology. First, they need to get an understanding of Einsteinian physics, specifically space-time. Furthermore, they need to understand that speed bubbles are locked on in location to things like the planet, or a moving train. This would allow them to extrapolate that a bubble would stay in place on a spaceship as well. Finally, they need to have completely mechanized the metallic arts in order to get the ship off the ground so that this drive will even work, because it won't work on a planet. Furthermore, I expect them to have figured out how to create spirit webs with allomantic powers that can draw more investiture than even lerasium mistborn would be able to, much less any allomancer born to their powers in that era. So, here's what I'm imagining Era 4 to look like. 

A long, thin ship stands up on the ground, surrounded by a large, ringed tower. The tower activates, each ring activating a constant upward steelpush on the ship, sending it up and up, faster and faster, like an allomantic rail gun. Once in space, the ship stores its weight as it determines its course by going through similar, larger rings in space. Then, in the back, a large, powerful cadmium bubble activates, and in the front, a similar bendalloy bubble activates. Space time is compressed in the front, and expanded in the back, sending the ship to speeds that are faster than light. In the middle of the long ship, between the large bubbles, smaller, nested cadmium bubbles multiplicatively slow down time for the people waiting through the voyage. It probably also has another form of propulsion, perhaps a solar sail or ionic engines or something. It could land something on a new planet by simply finding a large enough metal deposit to push against as it descends. 

Now, my hope is that either I will get the chance to ask him about space compression next time I see him, or that someone else will get around to asking it. Given that he worked with Peter closely on the physics of speed bubbles, and that an understanding of space time is fairly universal, I can't imagine that he would create a power like speed bubbles where they manipulate time in such a way, and NOT have it affect space as well, especially as it affecting space leads into exactly the sorts of discoveries we expect from scadrial at some point. Frankly, I'm more surprised that I can't seem to remember this being mentioned before. 

edit: oh, and I figured I should mention this thought about Era 4 here. Brandon has always made it clear Era 4 isn't going to be the Avengers. My thought is that instead, it's going to be more akin to Star Trek. With a more focused plot line. 

Edited December 29, 2018 by Steeldancer
formatting for ease of reading. And I spelled Alcubierre wrong.

[+Extesian he/him]

I dig it. Don't know enough to know if there are physics issues (especially whatever factor there is with compressing space and if that should be noticeable to an outside observer) but makes a lot of sense. 

[HSuperLee]

I've seen this theory proposed more than once on this site. But yes, the general impression we've had is that the external temporal metals will provide Scandrian ftl. To my knowledge, Sanderson has RAFOed any further questions about it.

[Jace21 he/him]

9 minutes ago, HSuperLee said:

I've seen this theory proposed more than once on this site. But yes, the general impression we've had is that the external temporal metals will provide Scandrian ftl. To my knowledge, Sanderson has RAFOed any further questions about it.

You've seen this specific theory multiple times?

We all know Scadrial will achieve FTL, but I have never seen the OP's theory on the "how" here before.

I like it though, I can't believe I hadn't thought of it before, it seems exactly something Brandon would do and the physics seems to work.

[old man moomba he/him]

Love the "Allomantic Railgun" idea.

[Steeldancer he/him]

Ok, I’ve done more thinking upon FTL tech in other parts of the cosmere. Roshar is pretty obvious, you should be able to create something like an alcubierre drive, using Gravitational fabrials. (Gravitation fabrial and an antigravity fabrial). Sel has a harder time of things due to limitation of their abilities by area, but with connection investiture like in secret history, so long as that investiture can still be used to power Aons or something of that ilk, they should have enough of variety in the magic system to pull off FTL (although, I’m not sure what Aons would be used). The one that stumped me is Taldain, which Brandon states would have been first to FTL if autonomy hadn’t interfered. Thing is, their magic systems are drastically underwhelming, and I haven’t yet thought of another FTL system that would really fit the bill for a world like Taldain. But, Yata pointed out one thing Taldain has going for it- sand. The sand would make a great investiture battery. I’m not sure what they’ll do with these sandy investiture batteries, but they’d be easy to store and refill. I’m sure this has something to do with how they could achieve FTL tech. 

[Bigmikey357 he/him]

If Taldain would have been the first to achieve FTL, it would likely be due to Darkside technology rather than Cosmere magic. They had guns way before Scadrial gets them and Scadrial is the most technically advanced world us readers have spent much time in. Of course, we don't really know what magic looks like on Darkside. The most we know is that Darksiders can see into the infared spectrum (I think. Been awhile since I read WS prose).

[Steeldancer he/him]

7 hours ago, Bigmikey357 said:

If Taldain would have been the first to achieve FTL, it would likely be due to Darkside technology rather than Cosmere magic. They had guns way before Scadrial gets them and Scadrial is the most technically advanced world us readers have spent much time in. Of course, we don't really know what magic looks like on Darkside. The most we know is that Darksiders can see into the infared spectrum (I think. Been awhile since I read WS prose).

We know just enough about darkside magic to know it is even less dramatic than Sandmagery. I very, VERY much doubt that their magic is what will allow them to achieve FTL tech. I'm currently basing this all on the assumption that the FTL tech they use will make sense, it won't be just "oh it's a hyperdrive, it just gets them faster than light," there's going to be a distinct reasoning behind each technology that will allow FTL, probably tied to investiture in some way or another. 

[Bigmikey357 he/him]

Agreed on all points.

[Steeldancer he/him]

Hey everyone who commented on this thread, I asked brandon about it at FanX a week ago, and he basically confirmed it! I'll post the WoB on here once it gets uploaded to Arcanum, but I'm really fascinated to see what else there is to the alcubierre drive besides just the bubbles. 

[xinoehp512 he/him]

On 12/29/2018 at 4:45 PM, Steeldancer said:

speed bubbles compress space

How?

[Steeldancer he/him]

13 minutes ago, xinoehp512 said:

How?

Space time, my friend, space time. 

If you’re changing time, space will change along with it. It’s classic relativity, the fabric of space time and whatnot. 

[xinoehp512 he/him]

But how? How is it that space warps?

[+Invocation]

2 minutes ago, xinoehp512 said:

But how? How is it that space warps?

I don't know if this counts (I'm not very good at physics) but would the refraction of entering objects count?

[xinoehp512 he/him]

That's true.

I wonder how that would stack up with crazy-nested bubbles...

[+Invocation]

1 minute ago, xinoehp512 said:

That's true.

I wonder how that would stack up with crazy-nested bubbles...

Very radical changes, probably. A refraction on crossing each of the borders in a random direction would end up with some wild stuff, especially in something like a Gatling gun or some other rotary.

[Arith Matic he/him]

could ettmetal possibly fit into all of this?

 

could the aforementioned alcubierre drive be created with an ettmetal machine of sorts, or would it run out of charge early, like we see the ettmetal machine do in the bands of mourning?

[Ethan_sedai he/him]

Ok, I was uncertain about it warping space, because I think the reason time is related to space is the speed of light or something, but since there is no redshift with speed bubbles, that screws my understanding of spacetime over. 

But if Brandon confirmed it, I’ll believe it.

[Karger he/him]

14 minutes ago, Ethan_Sedai said:

Ok, I was uncertain about it warping space, because I think the reason time is related to space is the speed of light or something, but since there is no redshift with speed bubbles, that screws my understanding of spacetime over. 

But if Brandon confirmed it, I’ll believe it.

Think of space like a conveyor belt.  Nothing on the belt can go faster then light but nothing governs how fast the belt itself can move.  When opening a bubble its like stretching the belt so that everything takes longer.  Excess energy is pulled into and out of the spiritual realm to account for Redshift at the boundary.

[Ethan_sedai he/him]

2 minutes ago, Karger said:

Excess energy is pulled into and out of the spiritual realm to account for Redshift at the boundary

Is that why there isn’t redshift? I never knew that.

[Karger he/him]

30 minutes ago, Ethan_Sedai said:

Is that why there isn’t redshift? I never knew that.

I believe so.  At the barrier energy is pulled into or out of the spiritual realm(depending on bubble).  This is one of the reasons that shooting into or out of them is next to impossible to do accurately.

[+Invocation]

37 minutes ago, Karger said:

Think of space like a conveyor belt.  Nothing on the belt can go faster then light but nothing governs how fast the belt itself can move.  When opening a bubble its like stretching the belt so that everything takes longer.  Excess energy is pulled into and out of the spiritual realm to account for Redshift at the boundary.

34 minutes ago, Ethan_Sedai said:

Is that why there isn’t redshift? I never knew that.

That might be it. We won't know for sure until Sandman tells us what his Fourth Law of Thermodynamics is that apparently explains all that stuff.

[Bookish Ocelot she/her]

Redshift only starts occurring at really really large distances. Like The-Universe-Expanding—Over-Hundred-Year’s distances. We can use redshift to measure how far away a thing is getting from Earth. But it usually isn’t visible to the human eye. It’s done with a spectrogram.